Warranty Reserve and Accrual for Loss Contracts Related to Service (Detail) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Warranty Reserve and Accrual for Loss Contracts Related to Service | ||
| Beginning balance - January 1 | $ 406 | $ 1,311 |
| Additions for current period deliveries | 42 | 230 |
| Reductions for payments made | (263) | (1,135) |
| Ending balance - December 31 | $ 185 | $ 406 |